科学家们正在研究如何保护科罗拉多河中的濒危尖头鲑。

Scientists are studying how to protect the endangered ___pikeminnow in the Colorado River.

为了保护本地鱼类，当局建议捕捞并清除这种以小鱼为食的掠食性鱼类。

To protect native fish, authorities recommend catching and removing ___pikeminnows that prey on smaller fish.